The objective of this study was to observe the possible uptake of antibody to dopamine-beta-hydroxylase (ADBH) into central nervous system noradrenergic neurons following stereotaxic intraventricular or intracerberal injection of ADBH. In vivo administration of ADBH resulted in the specific uptake and localization of the antibody-DBH complex only in noradrenergic neurons (fibers and cell bodies). The suggestion that ADBH was taken up by noradrenergic nerve terminals and transported to neural cell bodies via retrograde processes is supported by three lines of evidence: (1) time course studies, (2) unilateral ADBH injection into the hypothalamic dorsal noradrenergic bundle resulted in the labelling of cell bodies in the locus coeruleus, and (3) bilateral transection of this bundle proximal to the injection site prevented the arrival of ADBH into locus coeruleus cells.